The physiology of the human body is such that, when the body rests on a support, say a mattress of a bed or a chair seat, there will always be certain body portions subject to excessive pressure relative to other body portions. Should such peak local pressure be maintained for a prolonged period, and not be relieved by changing the posture of lying or sitting, damage will be caused to the tissue, referred to in medical literature as pressure sores, or decubitus ulcers. The development of pressure sores is aggravated by excessive temperature and perspiration.
Various solutions have been proposed in cases here the patient is unable to help himself by changing his lying position (paralyzed or geriatric cases), such as vibrating or massaging means attached to the bed. None of the prior art solutions has in fact been widely used, being rejected as either too costly and/or ineffective.
It is therefore the general object of the present invention to provide means associated with body rests that will effectively overcome the disadvantages of the known solutions.
It is a further object of the invention to provide body rests divided into a plurality of individual, local body rest members which are adapted to be displaced to relieve any excessive local pressure to which they were subjected for a prolonged time.
It is a still further object of the invention to provide a control system responsive to pressure vs. time parameters for displacing--i.e. lowering--any one of the displaceable members.
It is a still further object of the invention that such displacement be effected in a stepwise manner, by having each support member suspendingly held by fluid pressure, e.g by an air or other gas cushion, and, once in a while, as sensed by the control system, relieving a defined, fixed volume of the gas from the respective cushion.